// This source file is part of the polarphp.org open source project
//
// Copyright (c) 2017 - 2019 polarphp software foundation
// Copyright (c) 2017 - 2019 zzu_softboy <zzu_softboy@163.com>
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://polarphp.org/LICENSE.txt for license information
// See https://polarphp.org/CONTRIBUTORS.txt for the list of polarphp project authors
//
// Created by polarboy on 2018/06/08.

/*
 * This code is derived from (original license follows):
 *
 * This is an OpenSSL-compatible implementation of the RSA Data Security, Inc.
 * Md5 Message-Digest Algorithm (RFC 1321).
 *
 * Homepage:
 * http://openwall.info/wiki/people/solar/software/public-domain-source-code/Md5
 *
 * Author:
 * Alexander Peslyak, better known as Solar Designer <solar at openwall.com>
 *
 * This software was written by Alexander Peslyak in 2001.  No copyright is
 * claimed, and the software is hereby placed in the public domain.
 * In case this attempt to disclaim copyright and place the software in the
 * public domain is deemed null and void, then the software is
 * Copyright (c) 2001 Alexander Peslyak and it is hereby released to the
 * general public under the following terms:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted.
 *
 * There's ABSOLUTELY NO WARRANTY, express or implied.
 *
 * (This is a heavily cut-down "BSD license".)
 *
 * This differs from Colin Plumb's older public domain implementation in that
 * no exactly 32-bit integer data type is required (any 32-bit or wider
 * unsigned integer data type will do), there's no compile-time endianness
 * configuration, and the function prototypes match OpenSSL's.  No code from
 * Colin Plumb's implementation has been reused; this comment merely compares
 * the properties of the two independent implementations.
 *
 * The primary goals of this implementation are portability and ease of use.
 * It is meant to be fast, but not as fast as possible.  Some known
 * optimizations are not included to reduce source code size and avoid
 * compile-time configuration.
 */

#include "polarphp/utils/Md5.h"
#include "polarphp/basic/adt/ArrayRef.h"
#include "polarphp/basic/adt/StringRef.h"
#include "polarphp/utils/Endian.h"
#include "polarphp/utils/Format.h"
#include "polarphp/utils/RawOutStream.h"
#include <array>
#include <cstdint>
#include <cstring>

// The basic Md5 functions.

// F and G are optimized compared to their RFC 1321 definitions for
// architectures that lack an AND-NOT instruction, just like in Colin Plumb's
// implementation.
#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z) ((y) ^ ((z) & ((x) ^ (y))))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | ~(z)))

// The Md5 transformation for all four rounds.
#define STEP(f, a, b, c, d, x, t, s)                                           \
   (a) += f((b), (c), (d)) + (x) + (t);                                         \
   (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s))));                   \
   (a) += (b);

// SET reads 4 input bytes in little-endian byte order and stores them
// in a properly aligned word in host byte order.
#define SET(n)                                                                 \
   (m_block[(n)] =                                                                \
   (Md5U32PlusType) ptr[(n) * 4] | ((Md5U32PlusType) ptr[(n) * 4 + 1] << 8) |    \
   ((Md5U32PlusType) ptr[(n) * 4 + 2] << 16) |                                \
   ((Md5U32PlusType) ptr[(n) * 4 + 3] << 24))
#define GET(n) (m_block[(n)])

namespace polar {
namespace utils {

/// This processes one or more 64-byte data blocks, but does NOT update
///the bit counters.  There are no alignment requirements.
const uint8_t *Md5::body(ArrayRef<uint8_t> data)
{
   const uint8_t *ptr;
   Md5U32PlusType a, b, c, d;
   Md5U32PlusType saved_a, saved_b, saved_c, saved_d;
   unsigned long size = data.getSize();

   ptr = data.getData();

   a = this->a;
   b = this->b;
   c = this->c;
   d = this->d;

   do {
      saved_a = a;
      saved_b = b;
      saved_c = c;
      saved_d = d;

      // Round 1
      STEP(F, a, b, c, d, SET(0), 0xd76aa478, 7)
            STEP(F, d, a, b, c, SET(1), 0xe8c7b756, 12)
            STEP(F, c, d, a, b, SET(2), 0x242070db, 17)
            STEP(F, b, c, d, a, SET(3), 0xc1bdceee, 22)
            STEP(F, a, b, c, d, SET(4), 0xf57c0faf, 7)
            STEP(F, d, a, b, c, SET(5), 0x4787c62a, 12)
            STEP(F, c, d, a, b, SET(6), 0xa8304613, 17)
            STEP(F, b, c, d, a, SET(7), 0xfd469501, 22)
            STEP(F, a, b, c, d, SET(8), 0x698098d8, 7)
            STEP(F, d, a, b, c, SET(9), 0x8b44f7af, 12)
            STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17)
            STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22)
            STEP(F, a, b, c, d, SET(12), 0x6b901122, 7)
            STEP(F, d, a, b, c, SET(13), 0xfd987193, 12)
            STEP(F, c, d, a, b, SET(14), 0xa679438e, 17)
            STEP(F, b, c, d, a, SET(15), 0x49b40821, 22)

            // Round 2
            STEP(G, a, b, c, d, GET(1), 0xf61e2562, 5)
            STEP(G, d, a, b, c, GET(6), 0xc040b340, 9)
            STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14)
            STEP(G, b, c, d, a, GET(0), 0xe9b6c7aa, 20)
            STEP(G, a, b, c, d, GET(5), 0xd62f105d, 5)
            STEP(G, d, a, b, c, GET(10), 0x02441453, 9)
            STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14)
            STEP(G, b, c, d, a, GET(4), 0xe7d3fbc8, 20)
            STEP(G, a, b, c, d, GET(9), 0x21e1cde6, 5)
            STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9)
            STEP(G, c, d, a, b, GET(3), 0xf4d50d87, 14)
            STEP(G, b, c, d, a, GET(8), 0x455a14ed, 20)
            STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5)
            STEP(G, d, a, b, c, GET(2), 0xfcefa3f8, 9)
            STEP(G, c, d, a, b, GET(7), 0x676f02d9, 14)
            STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20)

            // Round 3
            STEP(H, a, b, c, d, GET(5), 0xfffa3942, 4)
            STEP(H, d, a, b, c, GET(8), 0x8771f681, 11)
            STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16)
            STEP(H, b, c, d, a, GET(14), 0xfde5380c, 23)
            STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4)
            STEP(H, d, a, b, c, GET(4), 0x4bdecfa9, 11)
            STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16)
            STEP(H, b, c, d, a, GET(10), 0xbebfbc70, 23)
            STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4)
            STEP(H, d, a, b, c, GET(0), 0xeaa127fa, 11)
            STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16)
            STEP(H, b, c, d, a, GET(6), 0x04881d05, 23)
            STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4)
            STEP(H, d, a, b, c, GET(12), 0xe6db99e5, 11)
            STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16)
            STEP(H, b, c, d, a, GET(2), 0xc4ac5665, 23)

            // Round 4
            STEP(I, a, b, c, d, GET(0), 0xf4292244, 6)
            STEP(I, d, a, b, c, GET(7), 0x432aff97, 10)
            STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15)
            STEP(I, b, c, d, a, GET(5), 0xfc93a039, 21)
            STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6)
            STEP(I, d, a, b, c, GET(3), 0x8f0ccc92, 10)
            STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15)
            STEP(I, b, c, d, a, GET(1), 0x85845dd1, 21)
            STEP(I, a, b, c, d, GET(8), 0x6fa87e4f, 6)
            STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10)
            STEP(I, c, d, a, b, GET(6), 0xa3014314, 15)
            STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21)
            STEP(I, a, b, c, d, GET(4), 0xf7537e82, 6)
            STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10)
            STEP(I, c, d, a, b, GET(2), 0x2ad7d2bb, 15)
            STEP(I, b, c, d, a, GET(9), 0xeb86d391, 21)

            a += saved_a;
      b += saved_b;
      c += saved_c;
      d += saved_d;

      ptr += 64;
   } while (size -= 64);

   this->a = a;
   this->b = b;
   this->c = c;
   this->d = d;

   return ptr;
}

Md5::Md5() {}

/// Incrementally add the bytes in \p Data to the hash.
void Md5::update(ArrayRef<uint8_t> data)
{
   Md5U32PlusType savedLow;
   unsigned long used, free;
   const uint8_t *ptr = data.getData();
   unsigned long size = data.getSize();

   savedLow = m_low;
   if ((m_low = (savedLow + size) & 0x1fffffff) < savedLow) {
      m_hight++;
   }
   m_hight += size >> 29;
   used = savedLow & 0x3f;
   if (used) {
      free = 64 - used;
      if (size < free) {
         memcpy(&m_buffer[used], ptr, size);
         return;
      }
      memcpy(&m_buffer[used], ptr, free);
      ptr = ptr + free;
      size -= free;
      body(polar::basic::make_array_ref(m_buffer, 64));
   }
   if (size >= 64) {
      ptr = body(polar::basic::make_array_ref(ptr, size & ~(unsigned long) 0x3f));
      size &= 0x3f;
   }

   memcpy(m_buffer, ptr, size);
}

/// Add the bytes in the StringRef \p Str to the hash.
// Note that this isn't a string and so this won't include any trailing NULL
// bytes.
void Md5::update(StringRef str)
{
   ArrayRef<uint8_t> sval((const uint8_t *)str.getData(), str.getSize());
   update(sval);
}

/// Finish the hash and place the resulting hash into \p result.
/// \param Result is assumed to be a minimum of 16-bytes in size.
void Md5::final(Md5Result &result)
{
   unsigned long used, free;
   used = m_low & 0x3f;
   m_buffer[used++] = 0x80;
   free = 64 - used;
   if (free < 8) {
      memset(&m_buffer[used], 0, free);
      body(polar::basic::make_array_ref(m_buffer, 64));
      used = 0;
      free = 64;
   }
   memset(&m_buffer[used], 0, free - 8);
   m_low <<= 3;
   endian::write32le(&m_buffer[56], m_low);
   endian::write32le(&m_buffer[60], m_hight);

   body(polar::basic::make_array_ref(m_buffer, 64));

   endian::write32le(&result[0], a);
   endian::write32le(&result[4], b);
   endian::write32le(&result[8], c);
   endian::write32le(&result[12], d);
}

SmallString<32> Md5::Md5Result::getDigest() const
{
   SmallString<32> str;
   RawSvectorOutStream res(str);
   for (int i = 0; i < 16; ++i) {
      res << format("%.2x", m_bytes[i]);
   }
   return str;
}

void Md5::stringifyResult(Md5Result &result, SmallString<32> &str)
{
   str = result.getDigest();
}

std::array<uint8_t, 16> Md5::hash(ArrayRef<uint8_t> data)
{
   Md5 hash;
   hash.update(data);
   Md5::Md5Result res;
   hash.final(res);
   return res;
}

} // utils
} // polar
